Software / code / prosody
File
plugins/mod_invites_register.lua @ 13801:a5d5fefb8b68 13.0
mod_tls: Enable Prosody's certificate checking for incoming s2s connections (fixes #1916) (thanks Damian, Zash)
Various options in Prosody allow control over the behaviour of the certificate
verification process For example, some deployments choose to allow falling
back to traditional "dialback" authentication (XEP-0220), while others verify
via DANE, hard-coded fingerprints, or other custom plugins.
Implementing this flexibility requires us to override OpenSSL's default
certificate verification, to allow Prosody to verify the certificate itself,
apply custom policies and make decisions based on the outcome.
To enable our custom logic, we have to suppress OpenSSL's default behaviour of
aborting the connection with a TLS alert message. With LuaSec, this can be
achieved by using the verifyext "lsec_continue" flag.
We also need to use the lsec_ignore_purpose flag, because XMPP s2s uses server
certificates as "client" certificates (for mutual TLS verification in outgoing
s2s connections).
Commit 99d2100d2918 moved these settings out of the defaults and into mod_s2s,
because we only really need these changes for s2s, and they should be opt-in,
rather than automatically applied to all TLS services we offer.
That commit was incomplete, because it only added the flags for incoming
direct TLS connections. StartTLS connections are handled by mod_tls, which was
not applying the lsec_* flags. It previously worked because they were already
in the defaults.
This resulted in incoming s2s connections with "invalid" certificates being
aborted early by OpenSSL, even if settings such as `s2s_secure_auth = false`
or DANE were present in the config.
Outgoing s2s connections inherit verify "none" from the defaults, which means
OpenSSL will receive the cert but will not terminate the connection when it is
deemed invalid. This means we don't need lsec_continue there, and we also
don't need lsec_ignore_purpose (because the remote peer is a "server").
Wondering why we can't just use verify "none" for incoming s2s? It's because
in that mode, OpenSSL won't request a certificate from the peer for incoming
connections. Setting verify "peer" is how you ask OpenSSL to request a
certificate from the client, but also what triggers its built-in verification.
| author | Matthew Wild <mwild1@gmail.com> |
|---|---|
| date | Tue, 01 Apr 2025 17:26:56 +0100 |
| parent | 13011:16b47c3b44f3 |
| child | 13843:87dd8639f08f |
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local st = require "prosody.util.stanza"; local jid_split = require "prosody.util.jid".split; local jid_bare = require "prosody.util.jid".bare; local rostermanager = require "prosody.core.rostermanager"; local require_encryption = module:get_option_boolean("c2s_require_encryption", module:get_option_boolean("require_encryption", true)); local invite_only = module:get_option_boolean("registration_invite_only", true); local invites; if prosody.process_type == "prosody" then invites = module:depends("invites"); if invite_only then module:depends("register_ibr"); end end local legacy_invite_stream_feature = st.stanza("register", { xmlns = "urn:xmpp:invite" }):up(); local invite_stream_feature = st.stanza("register", { xmlns = "urn:xmpp:ibr-token:0" }):up(); module:hook("stream-features", function(event) local session, features = event.origin, event.features; -- Advertise to unauthorized clients only. if session.type ~= "c2s_unauthed" or (require_encryption and not session.secure) then return end features:add_child(legacy_invite_stream_feature); features:add_child(invite_stream_feature); end); -- XEP-0379: Pre-Authenticated Roster Subscription module:hook("presence/bare", function (event) local stanza = event.stanza; if stanza.attr.type ~= "subscribe" then return end local preauth = stanza:get_child("preauth", "urn:xmpp:pars:0"); if not preauth then return end local token = preauth.attr.token; if not token then return end local username, host = jid_split(stanza.attr.to); local invite, err = invites.get(token, username); if not invite then module:log("debug", "Got invalid token, error: %s", err); return; end local contact = jid_bare(stanza.attr.from); module:log("debug", "Approving inbound subscription to %s from %s", username, contact); if rostermanager.set_contact_pending_in(username, host, contact, stanza) then if rostermanager.subscribed(username, host, contact) then invite:use(); rostermanager.roster_push(username, host, contact); -- Send back a subscription request (goal is mutual subscription) if not rostermanager.is_user_subscribed(username, host, contact) and not rostermanager.is_contact_pending_out(username, host, contact) then module:log("debug", "Sending automatic subscription request to %s from %s", contact, username); if rostermanager.set_contact_pending_out(username, host, contact) then rostermanager.roster_push(username, host, contact); module:send(st.presence({type = "subscribe", from = username.."@"..host, to = contact })); else module:log("warn", "Failed to set contact pending out for %s", username); end end end end end, 1); -- Client is submitting a preauth token to allow registration module:hook("stanza/iq/urn:xmpp:pars:0:preauth", function(event) local preauth = event.stanza.tags[1]; local token = preauth.attr.token; local validated_invite = invites.get(token); if not validated_invite then local reply = st.error_reply(event.stanza, "cancel", "forbidden", "The invite token is invalid or expired"); event.origin.send(reply); return true; end event.origin.validated_invite = validated_invite; local reply = st.reply(event.stanza); event.origin.send(reply); return true; end); -- Registration attempt - ensure a valid preauth token has been supplied module:hook("user-registering", function (event) local validated_invite = event.validated_invite or (event.session and event.session.validated_invite); if invite_only and not validated_invite then event.allowed = false; event.reason = "Registration on this server is through invitation only"; return; elseif not validated_invite then -- This registration is not using an invite, but -- the server is not in invite-only mode, so nothing -- for this module to do... return; end if validated_invite and validated_invite.additional_data and validated_invite.additional_data.allow_reset then event.allow_reset = validated_invite.additional_data.allow_reset; end end); -- Make a *one-way* subscription. User will see when contact is online, -- contact will not see when user is online. function subscribe(host, user_username, contact_username) local user_jid = user_username.."@"..host; local contact_jid = contact_username.."@"..host; -- Update user's roster to say subscription request is pending... rostermanager.set_contact_pending_out(user_username, host, contact_jid); -- Update contact's roster to say subscription request is pending... rostermanager.set_contact_pending_in(contact_username, host, user_jid); -- Update contact's roster to say subscription request approved... rostermanager.subscribed(contact_username, host, user_jid); -- Update user's roster to say subscription request approved... rostermanager.process_inbound_subscription_approval(user_username, host, contact_jid); end -- Make a mutual subscription between jid1 and jid2. Each JID will see -- when the other one is online. function subscribe_both(host, user1, user2) subscribe(host, user1, user2); subscribe(host, user2, user1); end -- Registration successful, if there was a preauth token, mark it as used module:hook("user-registered", function (event) local validated_invite = event.validated_invite or (event.session and event.session.validated_invite); if not validated_invite then return; end local inviter_username = validated_invite.inviter; local contact_username = event.username; validated_invite:use(); if inviter_username then module:log("debug", "Creating mutual subscription between %s and %s", inviter_username, contact_username); subscribe_both(module.host, inviter_username, contact_username); rostermanager.roster_push(inviter_username, module.host, contact_username.."@"..module.host); end if validated_invite.additional_data then module:log("debug", "Importing roles from invite"); local roles = validated_invite.additional_data.roles; if roles and roles[1] ~= nil then local um = require "prosody.core.usermanager"; local ok, err = um.set_user_role(event.username, module.host, roles[1]); if not ok then module:log("error", "Could not set role %s for newly registered user %s: %s", roles[1], event.username, err); end for i = 2, #roles do local ok, err = um.add_user_secondary_role(event.username, module.host, roles[i]); if not ok then module:log("warn", "Could not add secondary role %s for newly registered user %s: %s", roles[i], event.username, err); end end elseif roles and type(next(roles)) == "string" then module:log("warn", "Invite carries legacy, migration required for user '%s' for role set %q to take effect", event.username, roles); module:open_store("roles"):set(contact_username, roles); end end end); -- Equivalent of user-registered but for when the account already existed -- (i.e. password reset) module:hook("user-password-reset", function (event) local validated_invite = event.validated_invite or (event.session and event.session.validated_invite); if not validated_invite then return; end validated_invite:use(); end);